11 research outputs found

    The first two centuries of colonial agriculture in the cape colony: A historiographical review∗

    Full text link

    A process supported by the utility BBPC for analysing Braun-Blanquet data on a personal computer

    No full text
    Many South African vegetation scientists use utilise the Braun-Blanquet methodology. The main aim of this paper is to describe an affordable, rapid and efficient process for analysing Braun-Blanquet phytosociological data sets on a personal computer. It describes a suite of utilities joining various phases and this makes the entire process possible

    The plant communities and species richness of the <i>Alepidea longifolia- Monocymbium ceresiiforme</i> High-altitude Grassland of northern KwaZulu-Natal

    No full text
    As part of a vegetation survey of the grasslands of northern KwaZulu-Natal, this survey was conducted within the Alepidea longifolia-Monocymbium ceresiiforme grassland of high altitudes. Releves were compiled in 156 stratified random sample plots. The data set was classified using TWINSPAN. Subsequent refinement by Braun-Blanquet procedures produced 15 plant communities. Species richness was determined for each community. According to naturalness and species richness two communities were selected as being of conservation importance. An ordination algorithm (DECORANA) was also applied to describe the relationships between the vegetation units and the physical environment

    Major Vegetation Types of the Soutpansberg Conservancy and the Blouberg Nature Reserve, South Africa

    Get PDF
    The Major Megetation Types (MVT) and plant communities of the Soutpansberg Centre of Endemism are described in detail, with special reference to the Soutpansberg Conservancy and the Blouberg Nature Reserve. Phytosociological data from 442 sample plots were ordinated using a DEtrended CORrespondence ANAlysis (DECORANA) and classified using TWo-Way INdicator SPecies ANalysis (TWINSPAN). The resulting classification was further refined with table-sorting procedures based on the Braun–Blanquet floristic–sociological approach of vegetation classification using MEGATAB. Eight MVT’s were identified and described as Eragrostis lehmanniana var. lehmanniana–Sclerocarya birrea subsp. caffra Blouberg Northern Plains Bushveld, Euclea divinorum–Acacia tortilis Blouberg Southern Plains Bushveld, Englerophytum magalismontanum–Combretum molle Blouberg Mountain Bushveld, Adansonia digitata–Acacia nigrescens Soutpansberg Arid Northern Bushveld, Catha edulis–Flueggia virosa Soutpansberg Moist Mountain Thickets, Diplorhynchus condylocarpon–Burkea africana Soutpansberg Leached Sandveld, Rhus rigida var. rigida–Rhus magalismontanum subsp. coddii Soutpansberg Mistbelt Vegetation and Xymalos monospora–Rhus chirendensis Soutpansberg Forest Vegetation

    Guidelines for phytosociological classifications and descriptions of vegetation in southern Africa

    No full text
    Changes in the environment are first observed in changes in the vegetation. Vegetation survey, classification and mapping form the basis on which informed and scientifically defendable decisions on the environment can be taken. The classification and mapping of vegetation is one of the most widely used tools for interpreting complex ecosystems. By identifying different plant communities we are essentially identifying different ecosystems at a particular hierarchical level. Phytosociologists in Europe have been involved in such studies following, in particular, the Braun-Blanquet approach since the early 1900s. In South Africa, such studies were undertaken on a limited basis from the early 1970s and have since then steadily increased. The surveying of the enormous diversity of South African vegetation is one of the objectives of phytosociological studies. The demand for such data has steadily increased over the past few years to guide conservation policies, biodiversity studies and ecosystem management. In South Africa, numerous publications on the vegetation of conservation and other areas in the different biomes have been produced over the last few decades. However, vegetation scientists in South Africa experience unique problems. The purpose of this article is therefore to provide an overview of the history and the specific focus of phytosociological studies in South Africa and to recommend minimum requirements and methods to be followed when conducting such studies. It is believed that the incorporation of these requirements will result in scientifically justifiable research of high quality by phytosociologists in South Africa. Conservation implications: Effective conservation cannot be obtained without a thorough knowledge of the ecosystems present in an area. Consistent vegetation classifications and descriptions form the basis of conservation and monitoring exercises to maintain biodiversity. The incorporation of these guidelines and requirements will facilitate quality phytosociological research in South Africa

    Evaluating herbivore management outcomes and associated vegetation impacts

    No full text
    African savannas are characterised by temporal and spatial fluxes that are linked to fluxes in herbivore populations and vegetation structure and composition. We need to be concerned about these fluxes only when management actions cause the system to shift towards a less desired state. Large herbivores are a key attribute of African savannas and are important for tourism and biodiversity. Large protected areas such as the Kruger National Park (KNP) manage for high biodiversity as the desired state, whilst private protected areas, such as those adjacent to the KNP, generally manage for high income. Biodiversity, sustainability and economic indicators are thus required to flag thresholds of potential concern (TPCs) that may result in a particular set of objectives not being achieved. In large conservation areas such as the KNP, vegetation changes that result from herbivore impact, or lack thereof, affect biodiversity and TPCs are used to indicate unacceptable change leading to a possible loss of biodiversity; in private protected areas the loss of large herbivores is seen as an important indicator of economic loss. Therefore, the first-level indicators aim to evaluate the forage available to sustain grazers without deleteriously affecting the vegetation composition, structure and basal cover. Various approaches to monitoring for these indicators were considered and the importance of the selection of sites that are representative of the intensity of herbivore use is emphasised. The most crucial step in the adaptive management process is the feedback of information to inform management decisions and enable learning. Feedback loops tend to be more efficient where the organisation’s vision is focused on, for example, economic gain, than in larger protected areas, such as the KNP, where the vision to conserve biodiversity is broader and more complex. Conservation implications: In rangeland, optimising herbivore numbers to achieve the management objectives without causing unacceptable or irreversible change in the vegetation is challenging. This manuscript explores different avenues to evaluate herbivore impact and the outcomes of management approaches that may affect vegetation
    corecore